UULE Parameters Explained: How Google Encodes Location in Search

If you've ever examined a Google Search URL closely, you may have noticed a mysterious parameter called uule. This encoded string is one of the most powerful—and least understood—parameters in Google's search infrastructure.

UULE is the mechanism Google uses to encode a specific geographic location directly into a search URL. It's the same technology that powers Google Ads location targeting, and understanding it gives SEO professionals and developers the ability to simulate searches from any location in the world.

What Does UULE Stand For?

UULE stands for User-Unified Location Encoding. It's a proprietary parameter developed by Google to standardize how geographic locations are communicated within search requests.

When you add a uule parameter to a Google Search URL, you're essentially telling Google: "Treat this search as if it originated from this specific place."

The Structure of a UULE Parameter

A UULE parameter looks like this:

&uule=w+CAIQICIYQ2hpY2FnbyxJbGxpbm9pcyxVbml0ZWQgU3RhdGVz

Let's break down the structure:

Prefix: w+CAIQICI

This is a fixed prefix that identifies the UULE format. The w+ indicates the encoding type, and CAIQICI is a standard header.

Length Character

The character immediately after the prefix represents the length of the encoded location name. Google uses a single character to encode lengths from 1 to 63, following this mapping:

Length	Character
1	A
2	B
3	C
...	...
26	Z
27	a
28	b
...	...

So for "Chicago,Illinois,United States" (31 characters), the length character would be e (the 31st character in the A-Z, a-z sequence).

Encoded Location Name

The remainder of the string is the Base64-encoded canonical place name. This is the full location name as it appears in Google's geotargets database.

For example:

• "Chicago,Illinois,United States" → Base64 → Q2hpY2FnbyxJbGxpbm9pcyxVbml0ZWQgU3RhdGVz

What is the Canonical Place Name?

The canonical place name is the official, standardized name for a location in Google's geotargets database. This database contains every location that Google Ads uses for targeting.

Canonical names follow a hierarchical format:

City,State/Province,Country

Examples:

• Chicago,Illinois,United States
• London,England,United Kingdom
• Sydney,New South Wales,Australia
• Tokyo,Japan

The exact format varies by country. Some countries include a state/province, while others go directly from city to country.

Google's Geotargets Database

The geotargets database is a publicly available CSV file that Google maintains for advertisers. It contains:

• Criteria ID — a unique numeric identifier for each location
• Canonical Name — the standardized location name
• Parent ID — the ID of the parent region
• Country Code — the ISO country code
• Target Type — whether it's a city, state, country, airport, etc.

As of 2026, the database includes over 100,000 entries covering cities, states, provinces, metro areas, airports, and countries worldwide.

UULE vs Criteria ID: Two Approaches to Location

Google supports two ways of specifying location in search contexts:

UULE (Direct Search)

• Used in regular Google Search URLs
• Encodes the canonical place name in Base64
• Works across google.com and country-specific domains
• Best for simulating organic search results

Criteria ID (Ads Preview)

• Used in Google Ads Preview Tool URLs
• Uses the numeric ID from the geotargets database
• Example: Chicago = 1016367
• Most accurate for previewing ad placements

Both methods point to the same underlying location data, but they're used in different contexts within Google's infrastructure.

Practical Applications

SEO Rank Checking

By constructing URLs with UULE parameters, SEO professionals can check rankings for any location without physically being there or using a VPN.

Cross-Regional Content Testing

Content teams can verify that their localized landing pages are being served correctly to users in specific cities.

Competitive Analysis

Marketers can analyze the competitive landscape in target markets by simulating searches from those locations.

Tool Development

Developers building SEO or marketing tools can programmatically generate UULE-encoded URLs to offer location-based search simulation features.

How to Generate a UULE Parameter

The process for generating a UULE string is:

1. Find the canonical place name in Google's geotargets database
2. Count the characters in the canonical name
3. Map the character count to the corresponding length character (A=1, B=2, ... Z=26, a=27, b=28, etc.)
4. Base64 encode the canonical place name
5. Concatenate: w+CAIQICI + length character + Base64 string

Example: New York

1. Canonical name: New York,New York,United States (31 characters)
2. Length character: e (31st position)
3. Base64 of "New York,New York,United States": TmV3IFlvcmssTmV3IFlvcmssVW5pdGVkIFN0YXRlcw==
4. UULE: w+CAIQICIeTmV3IFlvcmssTmV3IFlvcmssVW5pdGVkIFN0YXRlcw==

Important Limitations

• Google may override UULE: If your IP address strongly contradicts the UULE location, Google may partially ignore it or blend results
• Not all locations are supported: Only locations in Google's geotargets database can be encoded
• Spelling must be exact: The canonical name must precisely match Google's database entry, including commas and spacing
• Deprecated in some contexts: Google has been tightening access to this parameter, and it may not work in all scenarios indefinitely

Key Takeaways

• UULE is Google's method for encoding geographic location into search URLs
• It uses Base64 encoding of canonical place names from Google's geotargets database
• Understanding UULE allows programmatic location-based search simulation
• The geotargets database is publicly available and contains 100,000+ locations
• UULE and Criteria IDs are complementary approaches to the same underlying location data